Saturn's orange moon Titan peeks from behind two of Saturn's rings. Small, battered Epimetheus, another of Saturn's 62 moons, appears just above the rings. NASA's Cassini spacecraft has detected propylene, a chemical used to make food-storage containers, car bumpers and other consumer products, on Saturn's moon Titan. This is the first definitive detection of the plastic ingredient on any moon or planet, other than Earth. A small amount of propylene was identified in Titan's lower atmosphere by Cassini's Composite Infrared Spectrometer (CIRS). This instrument measures the infrared light, or heat radiation, emitted from Saturn and its moons in much the same way our hands feel the warmth of a fire. Propylene is the first molecule to be discovered on Titan using CIRS. By isolating the same signal at various altitudes within the lower atmosphere, researchers identified the chemical with a high degree of confidence.